| 摘要 |
A high intensity cold-rolled steel sheet with excellent burring property by controlling a process condition and alloy elements, and a manufacturing method for the same are disclosed. The method for manufacturing the high intensity cold-rolled steel sheet comprises a step of: 1) reheating a slab board consisting of 0.05 to 0.1 weight % of carbon (C), 0.1 to 0.5 weight % of silicon (Si), 1.0 to 2.0 weight % of manganese (Mn), 0.03 to 0.1 weight % of titanium (Ti), 0.2 to 0.7 weight % of tungsten (W), less than 0.006 weight % of nitrogen (N), residual ferrum (Fe), and impurities at the temperature of 1250 to 1300°C; 2) hot-rolling the reheated slab board at the temperature of 840 to 880°C; 3) firstly cooling the hot-rolled slab board at 580 to 620°C; 3) secondly cooling the cooled slab board at the average speed of 2 to 5°C/sec; 4) cold-rolling and acid-cleaning the secondly cooled slab board; 5) annealing the cold-rolled slab board at the sub-critical point, A1; 5) thirdly cooling the annealed slab board at 300 to 400°C; 6) constantly maintaining the temperature of the slab board at 300 to 400°C; 7) fourthly cooling the slab board up to the Martensite temperature. [Reference numerals] (AA) START; (BB) END; (S110) Slab reheating; (S120) Hot-rolling; (S130) Primary cooling; (S140) Secondary cooling |
